The following table gives the import and export (in million dollars) of a country : Year: 2010 2011 2012 2013Import: 150 175 170 200Export: 140 183 170 210The average trade balance (trade balance = export – import) is

The correct answer is (b).

The average trade balance is calculated by taking the average of the trade balances for each year. The trade balance for each year is calculated by subtracting the import value from the export value. The trade balances for each year are:

Year: 2010 2011 2012 2013Trade balance: -10 43 -30 10

The average trade balance is therefore:

(-10 + 43 – 30 + 10) / 4 = 2

Option (a) is incorrect because it is the average of the export values, not the trade balances. Option (c) is incorrect because it is the average of the import values, not the trade balances. Option (d) is incorrect because it is not a possible value for the trade balance.